The overall objective is to elucidate the role of a novel, epithelial tissue derived transforming growth factor (TGFe) in transformation of epithelial cells. Previous studies (19) have shown that (1) TGFe is distributed mainly in a variety of tissues both neoplastic and nonneoplastic; (2) TGFe stimulates soft agar growth of some epithelial cell lines; and (3) TGFe is likely involved in autostimulation of these cells. The studies are designed to test the hypothesis that TGFe is a novel growth factor involved in transformation of epithelial cells through autocrine or paracrine manner of stimulation. To prove that TGFe is indeed a novel growth factor, large quantities of TGFe will be purified using a multistep purification scheme which will include acid-ethanol extraction, molecular sieve chromatography, Con A-Sepharose or heparin sepharose affinity chromatography, and reverse phase-high pressure liquid chromatography. N-terminal amino acid sequence will be determined using a gas phase sequenator and comparison with primary sequences of other growth factors and proteins will be done. A radioreceptor binding assay will be developed. This will enable to test the hypothesis of autocrine or paracrine stimulation of epithelial cells by determining the presence of TGFe in media conditioned either by epithelial cells responsive to TGFe or by sarcoma cells unresponsive to it.